Computer data is vital to today's organizations, and content-based storage (sometimes referred to as content-addressable storage or CAS) content addressable storage system (such as DELL EMC XTREMIO) (hereinafter “XtremIO”) can support a rich set of advanced data services such as single data instance, compression, snapshots, etc., by decoupling storage access, logical volume address space, and physical on-disk location of data. Content-based storage stores data based on its content, and in certain configurations provides benefits such as providing inherent data deduplication and facilitating in-line data compress. Existing content-based storage systems may utilize an array of storage device such as solid-state drives (SSDs, also known as solid-state disks) to provide high performance scale-out storage. In systems such as this, volume and physical layout metadata can offer tremendous flexibility in decoupling and virtualization. Logical volume metadata used with these systems can provide flexible mapping from logical address to data content references, also known as a hash handle. The logical volume metadata also can make snapshot and single instance storage operations highly efficient.
Within a content-based storage system, data may be organized into one or more volumes identified by respective logical unit numbers (LUNs). User applications can read/write data to/from a volume by specifying a LUN and an address (or “offset”) relative to the LUN. Some content-based storage systems allow for volumes to be cloned and for the creation of volume snapshots. To reduce system resource usage, internal data structures may be shared across different volumes and/or snapshots.
Some content-based storage systems serve as data protection systems that provide data replication, by creating a copy of an organization's production site data on a secondary backup storage system, and updating the backup with changes. Data replication systems generally operate either at the application level, at the file system level, or at the data block level. Continuous data protection systems can enable an organization to roll back to specific points in time. Some continuous data protection systems use a technology referred to as “journaling,” whereby a log is kept of changes made to the backup storage.